Electric switch



Jan. 9, 1951 H. THOMPSON 2,537,490

ELECTRIC SWITCH Filed June 20, 1947 INVENTOR.

2a Erma IX Hum 45011 BY /-y%// INEYS Patented Jan. 9, 1951 UNITED STATES PATENT OFFICE 2,537,490 ELECTRIC SWITCH Ervin H. Thompson, New York, N. Y. Application June 20, 1947, Serial No. 7 55,957

This invention relates to electric switches of the type commonly known as mercury switches, in which a pool of current-conducting liquid, usually mercury, is provided in a closed housing for opening and closing a circuit through associated electrodes, as a result of the position in which the device is placed. When tilted in one direction the liquid material contacts both electrodes within the housing and the associated electric circuit is closed. When tilted in another direction the liquid flows away from and out of contact with at least one of the electrodes to break the circuit.

As usually constructed, devices of this type have heretofore been designed to operate by tilting in one direction or in one plane only. Usually the closed housing is of elongated, horizontal construction with the electrodes so arranged that the switch is operative only when tilted in the vertical plane of its longitudinal axis.

An object of this invention is to provide a switch of this type constructed and arrangedto function so as to close an associated electric circuit when tilted in any direction from its open circuit position.

A further object is to provide a mercury switch in which a relatively small tilting movement in any direction will actuate the switch to close an associated circuit.

A further object is to provide an improved construction of electrode for switches of this type.

Other objects will become apparent from the following description taken in connection with the attached drawings showing several illustrative embodiments of the invention and wherein Fig. 1 is a view partly in side elevation and partly in section through a liquid contact or mercury switch constructed in accordance with one embodiment of the invention, showing the same in normal or open circuit position;

Fig. 2 is a transverse section on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 showing the switch tilted into operative circuit-closing position;

Fig. 4 is a view similar to Fig. 1 of a modified arrangement;

Fig. 5 is a view partly in plan and partly in horizontal section of a horizontal type switch;

Fig. 6 is a view partly in section on a plane at right angles to the section of Fig. 5;

Fig. 7 is a transverse section on the line of Fig. 6, and

1 Claim. (01. 200-152) Fig. 8 is a view similar to Fig. 6 of a modified arrangement.

In the present invention an elongated chamher or housing, closed and sealed, contains a pool of current-conducting liquid. In switches of this type, the housing is usually filled with hydrogen or the like. One electrode is positioned so as to be in substantially permanent contact with the pool in both operative and inoperative positions of the housing.

In the present invention, the second electrode is located just above the surface of the liquid pool when the housing is in inoperative or open circuit position. The electrode is so formed as to extend around the housing chamber onall sides thereof above the liquid pool so that the liquid will contact the second electrode to close the associated circuit when the device is tilted or rolled in any direction from its open circuit position. As a result, functioning of the switch is not dependent upon its being tilted in any specific plane or in any single direction, but resuits, on. the contrary, from substantially any movement which tilts, rolls, or shifts the housing out of open circuit position.

In the form shown in Figs. 14 inclusive, the open circuit position of the switch is obtained with the elongated housing chamber vertical, while in Figs. 5-8 inclusive, it is obtained when the chamber is horizontal.

Referring to the vertical type switch shown in Figs. 1-4 inclusive, the closed chamber H is formed by a housing or tube of any suitable material such, for example, as fiber, plastic, ordinary glass, Pyrex glass, or the like. It is of elongated, vertical construction and contains a pool 12 of liquid current-conducting material. Lead wires l3 are connected to spaced electrodes within the housing ll. As shown in Figs. 1 and 3, one electrode [4 extends downwardly through the center of the housing chamber and terminates adjacent the lower end thereof well below the 7 level of the liquid pool so as to be always in electrical contact therewith regardless of whether the housing is in vertical, open circuit position as shown in Fig. 1, or in tilted, operative posi-- tion as shown in Fig. 3. The other electrode l5 extends downwardly to a point just above the level of the pool when the housing is in open circuit position so as to be out of contact with the pool in such position. The electrode I5 is shaped so as to extend around all sides of the chamber H adjacent the wall thereof at a level just above the open circuit level of the pool. As illustrated, this is accomplished by shaping the lower end of the electrode 15in the form of a ring 16 which follows the contour of the inner wall of the housing chamber H. It will be apparent that movement of the housing in any direction from the open circuit position of Fig. 1 will cause the liquid material to flow into electrical contact with some portion of the electrode ring [6 so as to close the associated circuit, regardless of the direction in which the housing is tilted. Of course, when it is returned to vertical position the contact is broken.

As shown in Figs. 1, 2 and 3 the invention is applied to a vertical type switch in which both electrodes are mounted in and supported from one end of the tubular housing. In Fig. 4 the invention is shown in connection with a housing having the electrodes mounted in opposite ends. In this case the ring electrode 15, I9 is similar to that shown in Fig. 1, while the electrode IT, in permanent contact with the liquid pool is supported'in and extends through the bottom of the housing.

As shown in Figs. -8 inclusive, the invention is equally applicable to horizontal type liquid contact switches. In this case, a housing chamber 21 is generally similar to the chamber H but arranged to be in open circuit position when horizontal. Lead wires 22 connect with the electrodes within the housing, one electrode 23 being located adjacent and extending along the bottom face of the tube so as to be in substantially permanent electric contact with the pool 24 of conducting liquid. The other electrode 25 is so shaped as to extend around the inner wall of the housing chamber 2| at a level just above the level of the liquid pool so as to be just out of contact with the liquid when the chamber is in horizontal, open circuit position, as shown in Figs. 6, 7 and 8.

It will be apparent that the horizontal switch also will be actuated and the associated circuit closed by movement of the switch in substantially any direction either by tilting along its longitudinal axis, or by a rolling action about its axis, or by any combination of these two movements.

4 Such movement will cause the liquid 24 to contact some part of the electrode 25 and close the associated circuit. Returning the housing to the horizontal open circuit position illustrated breaks the circuit.

In Figs. 5, 6 and 7 the electrodes are both supported at one end of the housing 2 I. In Fig. 8 the submerged electrode 26 is supported in the end opposite to that supporting the electrode 25.

The invention is not intended to be limited to the forms shown which are understood as being illustrative only and not as limiting, as various changes in construction and arrangement may be made, all coming within the scope of the following claim:

An electric switch comprising a vertically extending, elongated housing, a pool of liquid current-conducting material in said housing, an electrode projecting downwardly through said housing into said pool so as to be electrically connected to said liquid material, and a second electrode extending downwardly through said housing to a point adjacent to and above the surface of said pool and. including a member extending entirely around the interior of said housing around said first electrode and adjacent the edge of said pool when said housing is in open circuit position, so as to be contacted by the material of said pool and thereby electrically connected to said first electrode when said housing is tilted in any direction out of open circuit position.

' ERV'IN H. THOMPSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

